Semiconductors Formation Assignment Help

Semiconductors Formation

pn junction when p – and n – type semiconductors of same material either Si or both Ge are joined to form a homojunction such a pn junction is formed.

Depletion layers close to the junction a layer exists devious of carriers due to the migration of carriers to the opposite sides the electrons migrate from n – side taken up by acceptor impurity atoms near the junction and become negatively ionized. Similarly donor impurity atoms close to the pn junction on n – side get positively ionized and hence create a potential barrier or factious battery.

Forward biasing if positive terminal of an external battery is connected to p – type and negative terminal to n- type width decreases.

Reverse biasing if positive terminal of the external battery is connected to n – type and negative terminal to p – type. The potential barrier increases. The deletion layer width increases and current is due to minority carrier.

Note that when forward biased by a voltage greater then, barrier potential, a large current flows and when reverse biased a very small current flows. Hence pn junction acts very closely like a value